Commit b182ecc8 authored Mar 19, 2015 by Josh Hunt Committed by Sasha Levin Mar 24, 2015

tcp: fix tcp fin memory accounting



[ Upstream commit d22e1537181188e5dc8cbc51451832625035bdc2 ]

tcp_send_fin() does not account for the memory it allocates properly, so
sk_forward_alloc can be negative in cases where we've sent a FIN:

ss example output (ss -amn | grep -B1 f4294):
tcp    FIN-WAIT-1 0      1            192.168.0.1:45520         192.0.2.1:8080
	skmem:(r0,rb87380,t0,tb87380,f4294966016,w1280,o0,bl0)
Acked-by: Eric Dumazet <edumazet@google.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 7f249ac5

net/ipv4/tcp_output.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -2739,15 +2739,11 @@ void tcp_send_fin(struct sock *sk)
		} else {
		/* Socket is locked, keep trying until memory is available. */
		for (;;) {
		skb = alloc_skb_fclone(MAX_TCP_HEADER,
		sk->sk_allocation);
		skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
		if (skb)
		break;
		yield();
		}

		/* Reserve space for headers and prepare control bits. */
		skb_reserve(skb, MAX_TCP_HEADER);
		/* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */
		tcp_init_nondata_skb(skb, tp->write_seq,
		TCPHDR_ACK \| TCPHDR_FIN);